The people in the archives were helpful and showed me the Union Church in Yokohama on a modern map. So I finally ended up here.
66-2 Yamate-cho, Naka-ku, Yokohama.
…obviously it is was a new building. So I went to talk to the pastors and they had no idea of the history of the church even after being there for more than 10 years. It seems history is lost with earthquakes and bombings.